As for the silver box, I dunno.... I believe everything I have is probably older than your F150, I think those are maybe like 5-10 years newer than what I've been guesstimated in age from sellers, but you know how that goes, no one knew how old this stuff is???
Some new kid trax, like a police car I fixed the other day, does have a circuit board soldered to the motors, but that's all I'm familiar with, but motors (on anything) can and do fail. ESPECIALLY on stuff that belongs to a kid, and used outside, it's fully understandable!
As far as motors go, I plan to stick with the stock motors, until I can go with the "live axle" stuff, be it belt or chain drive. I'd like to have a few "ESC's" from Wesley @ Eastcoastpowerup.com under my belt, after the lovely addition of CJB turbo timers and battery saver boards installed first. Most guys are finding that the stock doesn't perform all that bad compared with most any of the aftermarket motors. There isn't a definitive significant difference, from what I've read.
Air flow, now since I've only done a few fans, based on the limited scrap ones I had laying around, old PC fans, 12V, was I cut out the same size as the blade, with the hole saws I had. I have mine installed on the back side, blowing in, roughly at the motors. These are on jeeps, that see quite a bit of water, and I figured that there is enough gaps and cracks (around gearboxes, the seat, the shifter) for that added air to escape, and it "should" reduce the water from coming in. I was tempted to blow out, but figured that would pull water in, and it is hopefully easier to push out past the cracks than pull air in through muck? Am I right, wrong, I dunno, but that was my theory anyway. The first pair I did was on a mix mash jeep we call her work truck. The fans are wired straight off the motors, so when she runs in reverse, the fans suck in through the gaps, and since she's mostly driving forward they (2 in the back) push air in at the motors. It's worked well as far as I know, this work truck normally runs 12 Volt 28 amp hour, but some times 18V, and seldom 24. But she's beaten the snot out of it, and it keeps going! The 2 batteries are transferred to the back, under the seat, in the "ventilated" motor cavity under her butt, and that poor truck scoots my fat @$$ around, as a driver or on a crumby trailer, or in a 7 cubic yard plastic bin dumping yard trailer. I'm 200 lbs. She's also toted around all kinds of soil bags, retaining wall blocks, you name it. Stock motors are (knock on wood) still going strong, but I have a few spares.
Other guys are blowing 2 fans into the front of the "motor well" and using 2 fans to pull air out, spaced strategically to draw air across the motors. But I haven't bought any, so I spread thin the few I had laying around....
But the motors do run surprisingly hot, for a kids toy. When you compare technology, these aren't sophisticated technically, so there rather inefficient, and that does equate to the creation of heat. Plus the fact that it's scooting along a good 100 lbs of vehicle, kid, and battery, all the while traipsing through the backyard with grass and Bunny holes, it's kind of allowed to be hot. It's fully protected from lil fingers! But yes, expect it to be hot.
The grease.... I've been made aware that "some" greases are incompatible, so you can spread around what's in there, that's not all black and yucky, or you want to thoroughly clean out all that's in the gearbox and use like a white lithium grease. Oil will simply run out and make a big mess.
Check out Eastcoastpowerup, he does have motors, he's a member here, and tries to have tested in the real world components, and tries his best not to offer junk!
Maybe he's a tad higher than what you can find something from somewhere else, but I assure you, that you won't get as good support anywhere else! Bar none. This site was going through changes when I'd attempted to join, and I had emailed him I an effort to figure things out. He has immediate response, and I've read nothing but good reviews. I'd also read he quit supplying his kit due to product coming in the quality had suffered so he changed the kits. But everyone raves about his variable throttle electronic scooter controller (esc) kits. It takes a tremendous load off the motors, and allows for more speed, and far more control. It eliminates the shock load of the on/off switch that is the has pedal now.
And CJB offers a few products as well for a simpler and less expensive ease of charging and providing a boost!
Let me dig up a link for the gearbox, and the turbo timers.....
It was written originally a long time ago, so they weren't sure what was going to change, but you probably have #7 or 7R, which are the same, just thicker plastic gears.
AND last but not least is probably the best bang for the buck, the interface board and turbo timer thread.... definitely give it a read... and if you order one, let him know that I'm still thinking of him... financial problems on my end have prevented me from my original plans...